It is well known that emulsions of tall oil and combinations of tall oil products with petroleum residues and/or natural asphaltites can be prepared. A wide variety of methods have been used for this purpose and numerous methods are known to the art.
For example, emulsions prepared from blends of tall oil and/or tall oil pitch and naturally occurring or man made gilsonite are disclosed in U.S. Pat. No. 4,437,896, issued Mar. 20, 1984 to John F. Partanen. Additionally, U.S. Pat. No. 4,822,425 issued Apr. 18, 1989 to Richard M. Burch, discloses an emulsion comprising tall oil pitch, added rosin, an emulsifying agent and water. In both the Partanen and Burch patents, the pH and temperatures are not controlled during manufacture to prevent saponification or degradation of the acids or emulsion phase inversion from occurring.
Although various combinations of emulsions comprising tall oil are known to the art, there still exists a need in the industry for improved emulsions from tall oil, emulsified substantially free of other organic components. In part this is due to changes in the paving industries requiring more stringent performance criteria, as well as to changing environmental requirements and changes in the quality of the available tall oil products being supplied to the industry. Many existing methods for preparing emulsions of tall oil products cannot meet the new demands of the paving industry.
The present invention is characterized by the fact that the pH and temperatures during emulsion preparation are controlled to prevent saponification and neutralization of the fatty acids, resin acids and esters naturally occurring in tall oil products from occurring. Further, the emulsion is unique in that an emulsion is prepared without the need to add natural asphaltite or rosin to harden the end system or aid in emulsion stability. Emulsions prepared in accordance with the current invention can use standard refinery streams of tall oil products, without the need to adjust the streams with additional fatty acids or resin acids. The emulsions prepared in accordance with the current invention do not saponify or neutralize the acids or esters thereof contained in the tall oil. Emulsions prepared in accordance with the current invention thus are highly stable over extended periods of storage. The advantages of preserving the fatty acids and esters of the tall oil from saponification or neutralization are that the emulsions remain better able to meet the performance requirements of the paving industry, as well as expanding their use to other industries.